Heat sink system and assembly

ABSTRACT

A heat sink system with reduced airborne debris clogging, for cooling power electronics, the heat sink system including a heat sink having a plurality of fins, a housing configured to direct air flow around the side, top, and/or bottom of the heat sink and then through the fins of the heat sink at a back of the heat sink, and an inlet airway passage formed between a wall of the housing and said side, top, and/or bottom of the finned heat sink to allow air to pass within the housing, wherein said side, top, and/or bottom of the heat sink comprises at least one of said plurality of fins disposed directly in contact with the inlet airway passage.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of and claims priority benefit fromU.S. patent application Ser. No. 12/340,824 (filed on 22Dec. 2008, andreferred to herein as the “'824 Application”), which is a continuationof and claims priority benefit from U.S. patent application Ser. No.11/291,247 (filed on 1 Dec. 2005, and referred to herein as the “'247Application”). The entire disclosures of the '824 and '247 Applicationsare incorporated herein by reference in their entirety.

BACKGROUND

One or more embodiments of the inventive subject matter described hereinrelate to transportation vehicles that use relatively high powerelectronics that may require cooling systems and, more particularly, toa heat sink assembly for reducing airway blockage in the heat sinkassembly.

Vehicles such as locomotives and related transportation vehicles can beequipped with power electronics having cooling systems that use finnedheat sinks to aid in heat dissipation. These heat sinks are cooled byforced air. Previous heat sink designs have been used which employtypical fin arrangements with uniform spacing between the fins of theheat sinks. The cooling capability of the heat sink can depend on thenumber of fins, the spacing of the fins, the shape of the fins, and thesize of the fins. An example heat sink that is currently used inlocomotives is one developed by Aavid Thermalloy.

In some situations, airflow is directed to flow through the heat sink.Some known designs of heat sinks are susceptible to plugging withairborne debris such as diesel fumes, dust, dirt, and the like. Whenplugged, the effectiveness of the heat sink can be dramatically reduced,resulting in poorer cooling of the power electronics that rely on theheat sink for cooling and potentially increased failure rates of theelectronics due to excessive temperatures the electronics may experienceas a result of the effectiveness of the heat sink being reduced.

BRIEF DESCRIPTION

One or more embodiments of the presently described inventive subjectmatter relate to a system, assembly, and method for cooling electronicswith reduced airborne debris clogging in the heat sink. In oneembodiment, a heat sink system includes a heat sink having a pluralityof fins and a housing configured to direct air flow around a side, top,and/or bottom of the heat sink and through the fins of the heat sink ata back of the heat sink. The heat sink system also includes an inletairway passage formed between a wall of the housing and the side, top,and/or bottom of the finned heat sink to allow air to pass within thehousing. In one embodiment, the side, top, and/or bottom of the heatsink include at least one of the fins disposed directly in contact withthe inlet airway passage.

In another embodiment, in a cooling system having a heat sink systemwith air passing through an inlet airway passage to reach a plurality offins on a heat sink, the heat sink system includes a transition sealbetween the heat sink and the inlet airway passage. The heat sink systemmay also include a slot proximate the inlet airway passage to receive anouter fin of the heat sink. The outer fin is of a thickness to contactthe inner edges of the slot. At least one of the fins can be in thermalconnection with the inlet airway passage.

In another embodiment, a heat sink assembly includes a base elementdefining two dimensions of the heat sink assembly and a plurality offins attached to and extending from the base element. The heat sinkassembly also includes an inlet airway passage through which air travelsto reach the plurality of fins, and a transition seal between the heatsink and the inlet airflow passage. The heat sink assembly also includesa slot (such as a ribbed slot) that is located proximate the inletairflow passage to receive an outer fin of the heat sink, where theouter fin is of a thickness to contact inner edges of the slot. At leastone of the fins is in thermal connection with the inlet airflow passage.

BRIEF DESCRIPTION OF THE DRAWINGS

A more particular description of the inventive subject matter brieflydescribed above will be rendered by reference to specific embodimentsthereof that are illustrated in the appended drawings. Understandingthat these drawings depict only typical embodiments of the inventivesubject matter and are not therefore to be considered to be limiting ofits scope, the inventive subject matter will be described and explainedwith additional specificity and detail through the use of theaccompanying drawings in which:

FIG. 1 illustrates an example of a heat sink system in accordance withone embodiment;

FIG. 2 depicts an example embodiment of a cross-section of the heat sinkshown in FIG. 1 along line 2-2 in FIG. 1;

FIG. 3 depicts an example embodiment of a heat sink system in accordancewith another embodiment;

FIG. 4 depicts a top view of another embodiment of a heat sink system;

FIG. 5 illustrates a top view of one embodiment of the heat sink shownin FIG. 4;

FIG. 6 depicts a top view of an example embodiment of a heat sink systemin accordance with another embodiment;

FIG. 7 illustrates a perspective view of a heat sink system inaccordance with another embodiment;

FIG. 8 provides a detailed view of a transition seal of the heat sinksystem shown in FIG. 7 in accordance with one embodiment;

FIG. 9 depicts example leading edge designs for a heat sink fin;

FIG. 10 depicts example embodiments of various fin arrangements;

FIG. 11 illustrates one embodiment of a straddle mount fin supportsystem;

FIG. 12 is an example embodiment of a first fin arrangement;

FIG. 13 is another example embodiment of a second fin arrangement; and

FIG. 14 is another example embodiment of a third fin arrangement.

DETAILED DESCRIPTION

With reference to the figures, example embodiments of the inventivesubject matter will now be described. However, it should be noted that,though the presently described inventive subject matter describesvarious inventions or improvements that may be used in a heat sinksystem, these inventions or improvements may be used individually in asingle application or various combinations, including all versions atonce, may be used together. Toward this end, the example embodimentsdescribed herein should not be viewed as individual inventions since oneor more of the embodiments described herein can be used collectivelywith one or more other embodiments as well.

FIG. 1 illustrates an example of a heat sink system 100 in accordancewith one embodiment. The heat sink system 100 includes a housing 102with a heat sink 104 contained in the housing 102. The housing 102contains and channels the airflow 106 through the heat sink 104 to coolthe airflow 106. The heat sink 104 can be held in position by placementof the heat sink 104 between two or more solid divider walls 108 thatoppose each other. The divider walls 108 also separate the heat sink 104from inlet airflow passages 110 (also referred to herein as airflowpassages 110 or inlet paths 110) disposed on opposite sides of the heatsink 104. As shown in FIG. 1, the divider walls 108 define at least partof the inlet airflow passages 110 (e.g., by forming one side of each ofthe inlet airflow passages 110).

The heat sink 104 has fins 112 through which the airflow 106 isdirected. As the airflow 106 travels through the housing 102 and throughthe inlet airflow passageways 110, the airflow 106 experiences bends 114in the housing 102 and the inlet airflow passageways 110. As the airflow106 experiences the bends 114, heavier debris particles in the airflow106 may be forced to the outside of the radius of the bends 114, and mayimpinge upon a center 116 of a heat sink face 118 of the heat sink 104where the two inlet airflow passageways 110 converge. This phenomenonhas been further verified through debris ingestion testing of heat sinks104. Once debris clogging is initiated in the center 116 of the heatsink 104, plugging of the heat sink 104 can occur and can then proceedto increase, or grow, across the face 118 of the heat sink 104 towardthe divider walls 108.

With continued reference to FIG. 1, FIG. 2 depicts an example embodimentof a cross-section of the heat sink 104 along line 2-2 in FIG. 1. Theheat sink 104 includes the finned heat sink 104having a center-bypassarea 120. The fins 112 are laterally spaced apart by the same orapproximately the same separation distance 200 with at least two of thefins 112 laterally spaced apart by a greater separation distance 202than the other fins 112. The separation of the fins 112 by the greaterseparation distance 202 creates the bypass area 120 (also referred toherein as a bypass channel) in the heat sink 104. In the illustratedembodiment, the bypass area 120 provides an open channel through orbetween the center 116 of the heat sink fins 112 which allows forairborne debris to pass through the heat sink 104 (e.g., through thebypass area 120) without depositing on the inlet face 118 of the heatsink 104.

In one embodiment, the bypass area 120 can be formed by removing one ormore fins 112 from the heat sink 114. To offset such a removal of theheat sink fins 112, the overall size of the heat sink 104 may bemodified in overall width, fin height, length, and/or a number of fins112 to achieve equivalent thermal performance when compared to a heatsink that does not include the bypass area 120. This can be achievedwith constant spacing between the fins 112 and a bigger spacing in thebypass area 120, and/or by having a gradually increased spacing betweenthe fins 112 toward the center 116 of the heat sink 104. While thebypass area 120 is shown as being disposed in the center 116 of the face118 of the heat sink 104, the bypass area 120 may not be located in thecenter 116 of the face 118, but may located where a higher or thehighest concentration of debris is expected.

FIG. 3 depicts an example embodiment of a heat sink system 300 inaccordance with another embodiment. The heat sink system 300 includes ahousing 302 having housing guide vanes 304 and a finned heat sink 306.In one embodiment, the heat sink 306 may be similar to the heat sink 104shown in FIGS. 1 and 2. The vanes 304 can include walls disposed ininlet airflow passageways 308 of the housing 302 that can separate atleast some of the debris-laden air (“Dirty Airflow” in FIG. 3) of theairflow 106 that is flowing through the inlet airflow passageways 308from the airflow 106 that does not include debris or includes relativelyless debris (“Clean Airflow” in FIG. 3). For example, the vanes 304 aredisposed between, and spaced apart from, outer surfaces 310 of the inletairflow passageways 308 and opposing inner surfaces 312 of the inletairflow passageways 308. In the illustrated embodiment, at least part ofthe inner surfaces 312 includes divider walls 314, which may be similarto the divider walls 108 (shown in FIG. 1). Also as shown in FIG. 3, thevanes 304 may extend from an inlet face 316 of the heat sink 306 thatreceives the airflow 106 and partially along the inlet air passageways308. The vanes 304 may have shapes that are at least partially curved tofollow or approximately follow the curvature of the inlet airflowpassageways 308.

Including the vanes 304 in the housing 302 may further enhance theeffectiveness of the heat sink 306 having a bypass area that is similarto the bypass area 120 (shown in FIG. 1) described above. For example,the heat sink 104 may be included in the housing 302 as the heat sink306 with the bypass area 120 at least partially disposed between thevanes 304 such that the vanes 304 direct at least some of the DirtyAirflow into the bypass area 120. For example, the vanes 304 may be usedto more precisely control the amount and specific portion of the airflow106 that is diverted or directed through the bypass area 120 (e.g., theDirty Airflow) while allowing or directing the other airflow 106 (e.g.,the Clean Airflow) between the fins of the heat sink 104. The vanes 304may direct the heavier particles in the airflow 106 to the opening ofthe bypass area 120 so as to delay and/or avoid the initiation ofplugging of the spaces between the fins of the heat sink 306. Althoughonly two vanes 304 are illustrated, a larger number of vanes 304 may beincluded in the housing 302.

As shown in FIG. 3, the heat sink 306 may be mounted between two dividerwalls 314 which act to locate the heat sink 306 so as to channel theairflow 106 through the heat sink 306. Additional concepts of packagingthe heat sink 306 may be employed to increase the volume of the heatsink 306 without increasing the overall size and/or weight of the heatsink 306. Increasing the volume of the heat sink 306 may allow for oneor more fins 112 of the heat sink 306 to be removed or moved from theheat sink 306, which in turn can allow for increased separationdistances between the fins 112 without an associated loss in effectiveheat transfer area of the heat sink 306.

FIG. 4 depicts a top view of another embodiment of a heat sink system400. The heat sink system 400 includes a finned heat sink 402 within ahousing 404 that does not include the divider walls on opposite sides ofthe heat sink 402. For example, the housing 404 may be similar to thehousing 302 (shown in FIG. 3) with the divider walls 314 (shown in FIG.3) of the housing 300 removed.

As shown in FIG. 4, the airflow 106 flows through inlet airflowpassageways 406 disposed between the heat sink 402 and the housing 404.The airflow 106 moves around sides of the heat sink 402, curves alongbends 408 in the housing 404, and flows into an inlet face 410 of theheat sink 402. In the illustrated embodiment, the heat sink 402 does notinclude a bypass channel that is similar to the bypass channel 120 shownin FIG. 1. Alternatively, the heat sink 402 may include a bypasschannel.

FIG. 5 illustrates a top view of one embodiment of the heat sink 402shown in FIG. 4. Similar to the heat sink 104 (shown in FIG. 1), theheat sink 402 includes a plurality of fins 500, 502 that are laterallyspaced apart from each other. The fins 500, 502 include interior fins500 and outside fins 502, with the outside fins 502 disposed outside of,and on opposite sides of, the interior fins 500. For example, theoutside fins 502 may be located on opposite sides of the heat sink 402.

In the illustrated embodiment, the outside heat sink fins 502 may have alarger thickness dimension 504 than a thickness dimension 506 of theinterior fins 500. For example, the outside fins 502 may be made thickerthan the interior fins 500 so as to provide additional structuralsupport and/or to improve heat transfer rates of the heat sink system404. Increasing the thickness dimension 504 of the outside fins 502 canprovide the structural strength that is supplied by the divider walls314 (shown in FIG. 3) of the heat sink system 300. For example, with thedivider walls 314 not being present in the heat sink system 400, theoutside fins 502 can provide the structural strength to the heat sink402 that is otherwise provided by the divider walls 314 shown in FIG. 3.

Additionally, and as shown in FIG. 4, the outside heat sink fins 502 aredisposed along the inlet airflow passageways 406 of the housing 404.Positioning the outside heat sink fins 502 along the inlet airflowpassageways 406 causes the outside heat sink fins 502 to define at leastpart of the surfaces of the inlet airflow passageways 406. As airflow106 flows through the inlet airflow passageways 406, at least some ofthe airflow 106 may come into direct contact with the outside fins 502.The direct contact between the airflow 106 and the outside fins 502 cancause at least some thermal energy (e.g., heat) to be transferred fromthe airflow 106 to the heat sink 402 before the airflow 106 flowsthrough the heat sink 402.

FIG. 6 depicts a top view of an example embodiment of a heat sink system600 in accordance with another embodiment. The heat sink system 600includes a finned heat sink 602 having several heat sink fins 604. Theheat sink 602 is disposed within a housing 606. In contrast to the heatsink systems 300 (shown in FIG. 3) and 400 (shown in FIG. 4), the heatsink 602 extends across or through inlet airflow passageways 608 of theheat sink system 600, as shown in FIG. 6. For example, the heat sink 602may laterally extend across the entirety of the interior of the housing606.

FIG. 7 illustrates a perspective view of a heat sink system 700 inaccordance with another embodiment. FIG. 8 provides a detailed view of atransition seal 800 of the heat sink system 700 that is disposed betweena heat sink fin 702 of a heat sink 704 of the heat sink system 700 and ahousing 706 of the heat sink system 700 in accordance with oneembodiment. While the heat sink 700 is shown as including fins 702across the width of the heat sink 700, alternatively, one or more of thefins 702 may be removed or otherwise not present to form one or morebypass areas that are similar to the bypass areas 120 (shown in FIG. 1)of the heat sink 104 (shown in FIG. 1).

The housing 706 of the heat sink system 700 may be similar to thehousing 302 (shown in FIG. 3) of the heat sink system 300 (shown in FIG.3), except that the divider walls 312 (shown in FIG. 3) of the housing302 may be at least partially removed to form the transition seal 800.For example, at least a portion of the divider walls 312 may be removedexcept for a sloped portion 802 (shown in FIG. 8) at an end of thehousing 706. The sloped portion 802 is provided so as to have atransition seal between the heat sink 704 and the housing 706, includingan inlet airflow passage 708 and a weldment 804. Also, the housing 706can include a ribbed slot 806 to facilitate the easy location andapplication of a sealing member 808, such as a gasket. The sealingmember 808 can include a pressure sensitive adhesive on one side.Alternatively, another type of sealing material may be used.

The heat sink 704 is constructed with one or more outer or outside solidfins 702 that have shapes that are complimentary to the shapes of thesloped portion 802 of the transition seal 800. For example, the outsidefins 702 may have a convex portion with a radius of curvature thatmatches the radius of curvature of the concave portion in the transitionseal 800 that is formed by the sloped portion 802. The outer fins 702may have appropriate thicknesses so as to fit into the ribbed slots 806on opposite sides of the heat sink 704. The receipt of the outside fins702 into the ribbed slots 806 may compress the sealing members 808(e.g., gaskets) that run along the length of the outside fins 702. Theoutside fins 702 may act as the divider walls of the housing 700, suchas the outside fins 502 (shown in FIG. 5) of the heat sink system 500(shown in FIG. 5) act as the divider walls of the heat sink system 500.For example, the heat sink 704 may replace the divider walls 314. Theengagement between the outside fins 702 and the transition seal 800 mayform a seal to the airflow 106 such that the airflow 106 does not flowbetween the interface between the outside fins 702 and the slopedportion 802.

Even though a transition seal and slope portion are disclosed to providea seal between a heat sink and a base, alternatively, other embodimentsare possible to achieve the same connection wherein the heat sink fins702 are in thermal connection with a base. For example, the fins 702,having a rectangular shape, may have an end that extends to the weldment804 of the housing 706. The fins 702 that may be located in or adjacentto the inlet airflow passageways 708 may also be in thermal connectionwith the airflow passageways 708.

In the illustrated embodiment, a controlled restriction element 810 maybe provided at the same end of the housing 706 through which the airflow106 is received into the inlet airflow passageways 708. As illustratedin FIG. 7, the restriction element 810 is attached to the housing 706.Alternatively, the restriction element 810 can be part of or connectedto the heat sink 704. This restriction element 810 may be used tocontrol and/or regulate a pressure drop through the heat sink 704 due toincreased spacing between two or more of the fins 702 in the heat sink704. The restriction elements 810 can increase the pressure drop throughor across the heat sink system 700 by reducing cross-sectional sizes ofopenings 710 through which the airflow 106 is received into the inletairflow passageways 708.

In one embodiment, a plurality of heat sinks, such as up to thirty-six(36), may be used on a vehicle such as a locomotive. The pressure dropacross all of the heat sinks may be uniform. Thus, if a new heat sinkreplaces a current heat sink on the locomotive, the pressure drop acrossthis new heat sink may need to be uniform to the existing pressure dropsacross the other heat sinks. Toward this end, a restriction element 810is sized to ensure a uniform pressure drop across the replacement heatsink 704. By doing this, one heat sink may have a different sizedrestriction element 810 than another. This allows for ensuring that allfuture heat sinks are backward compatible with existing heat sinks in asystem, such as a locomotive.

For example, if the heat sink 704 includes one or more bypass areassimilar to the bypass area 120 (shown in FIG. 1) of the heat sink 104(shown in FIG. 1), then the pressure drop of the airflow 106 flowingthrough the heat sink 704 may be smaller than the pressure drop of theairflow 106 flowing through another heat sink that does not include abypass area, or that includes a smaller number of bypass areas orsmaller separation distances between the fins to form the bypass area.When multiple heat sink systems are arranged in parallel (such that theairflow 106 may flow through a plurality of the heat sink systems inparallel), the pressure drop across each of the heat sink systems may beequal or approximately equal to avoid substantially more airflow 106flowing through one or more of the heat sink systems relative to otherheat sink systems. In a vehicle or system having multiple heat sinksystems, including one or more of the heat sink systems 100, 300, 400,700 (shown in FIGS. 1, 3, 4, and 7) having heat sinks with one or morebypass areas 120, the restriction elements 810 may be included in theheat sink systems to increase the pressure drop across the heat sinksystems 100, 300, 400, 700 to be equal, approximately equal, or greaterthan the pressure drops across one or more other heat sink systemsconnected in parallel with the heat sink systems 100, 300, 400, and/or700. For example, if a vehicle is retrofitted with a heat sink havingone or more bypass areas 120 while one or more other heat sinks disposedin parallel do not have such bypass areas 120, the restriction elements810 may be used to increase the pressure drop across the heat sinkshaving the bypass areas up to the pressure drops across the other,non-retrofitted heat sinks.

In addition with respect to the housing 706, an access port 712 (notvisible but having a location or locations identified in FIG. 7) isprovided to facilitate inspection of heat sink clogging and/or cleaningof the heat sink 704.

FIG. 9 depicts example leading edge designs for a heat sink fin. Animproved leading edge design can assist in reducing a rate of pluggingof a heat sink, such as one or more of the heat sinks 108, 306, 402,602, 704 (shown in FIGS. 1, 3, 4, 6, and 7). In one embodiment of adesign of a heat sink fin 900, shown in in FIG. 9( a), a leading edge902 has a flat surface 904.

In another embodiment, a heat sink fin 906 has a leading edge 908 thatis shaped with a pointed, beveled edge 910, as illustrated in FIG. 9(b). Alternatively, a heat sink fin 912 may have a leading edge 914 thatincludes a rounded-off edge 916, as illustrated in FIG. 9( c). Theleading edges 902, 908, 914 may be disposed at one or more of theleading edge (e.g., the edge of the fin that contacts the airflow 106shown in FIG. 1 as the airflow 106 enters the heat sink having the fin)and/or a trailing edge (e.g., the opposite edge of the fin that contactsthe airflow 106 as the airflow 106 exits the heat sink having the fin)of the fins 900, 906, 912. In the case of fin designs that are not solidor continuous, such as the segmented or augmented fins disclosed below,one or more of the leading edges 902, 908, 914 may also be extended tothe leading and/or trailing edges of each of a plurality of fin segmentsof the fins.

In another embodiment, a surface finish of one or more fins in a heatsink may be altered to reduce a propensity of particles in the airflow106 (shown in FIG. 1) from sticking to the surface of the fins. Toachieve a non-stick fin, the fin may be processed to have a very finesurface finish, and/or coatings may be applied to produce a non-sticksurface. Teflon, fluoropolymers, PFA, PTFE, and FEP are some examples ofcoatings available that may be applied to reduce the propensity ofparticles in the airflow 106 from sticking to the fins.

FIG. 10 depicts example embodiments of various fin arrangements. Asillustrated, at least four different concepts for the fin arrangementsare shown. The concepts depicted include, in FIG. 10( a), an augmentedfin 1000 and, in FIG. 10( b), a straight fin 1002. The augmented fin1000 has parts 1004 of the fin 1000 that extend into the area whereairflow 106 (shown in FIG. 1) passes, which in turn may causeturbulence. The area of turbulence can result in debris buildup, orplugging, of a heat sink.

A configuration of a segmented fin 1006 depicted in FIG. 10( c) includesthe fin 1006 divided in a plurality of discrete segments 1008 that arespaced apart from each other. For example, as shown in FIG. 10( c), thesegments 1008 may be separated from each other along a length of the fin1006. The segmented fin 1006 may provide similar turbulence as theaugmented fin 1000 without providing edges or portions of the fin 1006that stick into the air stream of the airflow 106. By not having partsof the fin 1006 extending into the airflow 106, the probability ofplugging the heat sink with debris in the airflow 106 may be reduced.

FIG. 10( d) depicts design of a wavy fin 1010 that likewise attempts toincrease turbulence and heat transfer while removing leading edges thatpromote accretion of debris. As shown in FIG. 10( d), the wavy fin 1010includes an elongated body 1012 having an undulating shape. The body1012 may be continuous between opposite ends 1014, 1016 of the body1012.

In addition to providing enhanced clog resistance, edge treatment of thefins and various fin configurations may be performed or combined withother parameters such as varied fin geometry (e.g., thickness, height,and the like of the fins) and/or fin spacing, to tune and/or reduce theairflow-induced noise generation of the heat sink. For example, FIG. 11illustrates one embodiment of a straddle mount fin support system 1100that may be included in a heat sink. The system 1100 may be used toattach each of a plurality of fins 1102 to a base plate 1104 on a heatsink. As shown in FIG. 11, the system 1100 may include grooves 1106 thatreceive ends 1106 of the fins 1102.

Since the fin thickness may be small, the support of the fins 1102 maybe provided by bending portions 1110 of the fins 1102. Different fins1102 may be bent in opposite directions (e.g., as shown with respect tothe fins “A” and “B”) and then supporting the fins 1102 on the heat sinkbase 1104. For example, the fins 1102 that are bent in differentdirections may be coupled together to form a single fin when the ends1108 of the fins A and B are placed into neighboring grooves 1106 of thesystem 1100. Alternatively, thicker fins (such as the fins 112 shown inFIG. 2) may be used and/or more space may be provided between the finsand/or, the fins may be made thicker, such as illustrated in FIG. 2, soas to have a better heat transfer rate and to be able to support withoutbending portions of the fins in opposite directions.

FIGS. 12, 13, and 14 are example embodiments of fin arrangements 1200,1300, 1400 of varying lengths. The fin arrangements 1200, 1300, 1400include fins 1202, 1302, 1402 that may be included in one or more of theheat sinks described herein, such as the heat sink 602 shown in FIG. 6.The fin arrangements 1200, 1300, 1400 are described herein withreference to the heat sink system 600 shown in FIG. 6, but alternativelymay be used with one or more other heat sink systems described herein.

In one embodiment, FIGS. 12, 13, and 14 show one side of the fins in aheat sink, such as the fins on one side of a line through a heat sinktaken along line A-A of FIG. 6, wherein the fin arrangement 1200, 1300,and/or 1400 used in the heat sink is different than the fin arrangementshown in FIG. 6. For example, the areas designated as “inlet” in FIGS.12, 13, and 14 may include the fins 1202, 1302, 1402 that are in theheat sink 602 and that are located within one side of the inlet airflowpassageway 608. As illustrated, where the fins 1202, 1302, 1402 are inthe inlet airflow passageway 608, the fins 1202, 1302, 1402 in this areacan be of varied length to direct the path of the airflow 106.Alternatively, other varied lengths of the fins 1202, 1302, and/or 1402may be utilized to achieve a similar result in another embodiment.

As illustrated in FIG. 12, the fins 1202 in the inlet airflow passageway608 are longer toward the left outer edge of the heat sink 602 (in theview shown in FIG. 12) and then reduce in length the closer that thefins 1202 are to other heat sink fins 1202 that are used as an outlet1204 for the airflow 106. For example, the airflow 106 may flow into theheat sink 602 between the fins 1202 having varying lengths that decreaseas the fins 1202 are farther from the housing 606 that holds the heatsink 602. These fins 1202 may be referred to as “inlet fins.” When theairflow 106 passes ends of the inlet fins 1202, the airflow 106 may turnas shown in FIG. 12 due at least in part to the varying lengths of theinlet fins 1202.

Other fins 1202 disposed between the inlet fins 1202 and the line A-A inFIGS. 6 and 12 may conversely increase in length from the inlet fins1202 toward the line A-A. For example, the length of the fins 1202 mayincrease as the fins 1202 are farther from inlet fins 1202. The varyinglength inlet fins 1202 and outlet fins 1202 can cause the airflow 106 toflow through the inlet fins 1202, turn toward the outlet fins 1202, andflow through the outlet fins 1202 and out of the heat sink 602 at ornear the same end of the housing 600 that the airflow 106 is initiallyreceived into the heat sink 602. Alternatively, instead of the fins 1202having varying lengths, the inlet fins 1202 and/or outlet fins 1202 mayhave the same or approximately the same length and be cascaded (e.g.,staggered in position so that the ends of the fins 1202 are arranged asshown in FIG. 12) to turn the airflow 106 toward the outlet fins 1202.

In another example embodiment, shown in FIG. 13, the inlet fins 1202 ofthe embodiment shown in FIG. 12 may be removed such that the airflow 106moves through an inlet airflow passageway 1304 that is similar to theinlet airflow passageway 308 (shown in FIG. 3). The fins 1302 may bearranged similar to the outlet fins 1202 shown in FIG. 12 such that theinlet airflow passageway 1304 and/or the arrangement 1300 of the outletfins 1302 directs (e.g., turns) the airflow 106 to the outlet fins 1302.

In another example embodiment, as illustrated in FIG. 14, thearrangement 1400 includes the fins 1402 a that are of a longer lengthand curved and fins 1402 b that are of a shorter length and straight.The fins 1402 a may be disposed in and/or define an inlet airflowpassageway (e.g., similar to the inlet airflow passageway defined by theinlet fins 1202 of FIG. 12). Some of the curved fins 1402 a may becurved in a first direction toward the line A-A shown in FIGS. 6 and 14and may be referred to as inlet fins. Other curved fins 1402 b may becurved in an opposite, second direction toward the line A-A and may bereferred to as outlet fins.

The fins 1402 may define turning vanes that turn the airflow 106 fromthe inlet fins 1402 toward the outlet fins 1402 instead of having theturning vanes being part of the housing, such as in the embodiment shownin FIG. 3. As shown in FIG. 14, not every fin 1402 may be curved todefine a turning vane. For example, as illustrated in FIG. 14, everyother fin 1402 may be a curved fin 1402 a that has a vane as part of thefin 1402. Alternatively, all of the fins 1402 or a different number orarrangement of the fins 1402 may be curved and/or straight. The vanesdefined by the fins 1402 may be of varied lengths and can be used toimprove turning efficiency and flow distribution of the airflow 106through the heat sink. Though vanes are illustrated on the inlet fins1402, in another example embodiment the inlet fins 1402 may not includethe vanes.

When fins of varying length are used and/or curved fins are used, asdiscussed above, the housing for the heat sink may no longer berequired. For example, the housing 602 shown in FIG. 6 may not be usedas the fins 1202, 1204, 1302, and/or 1402 used in the heat sink 602 maydirect and control the movement of the airflow 106 in the heat sink 602.Toward this end, one less element is required within the cooling system,which results in a cost savings.

While one or more embodiments of the inventive subject matter has beendescribed in what is presently considered to be a preferred embodiment,many variations and modifications may become apparent to one of ordinaryskill in the art. Accordingly, it is intended that the inventive subjectmatter not be limited to the specific illustrative embodiment, but beinterpreted within the full spirit and scope of the appended claims.

1. A system comprising: a housing configured to receive airflow into aninlet airflow passageway; and a heat sink having plural fins spacedapart from each other and configured to receive the airflow between thefins from the inlet airflow passageway after the airflow has flowedthrough the inlet airflow passageway to reduce a temperature of theairflow, wherein at least one of the fins of the heat sink defines atleast a portion of the inlet airflow passageway.
 2. The system of claim1, wherein an outside fin of the fins in the heat sink is configured todefine a portion of the inlet airflow passageway along a length of theinlet airflow passageway.
 3. The system of claim 1, wherein at least twoof the fins in the heat sink are separated from each other by a largerseparation distance than other fins in the heat sink to define a bypasschannel of the heat sink.
 4. The system of claim 3, wherein the bypasschannel in the heat sink is positioned in the heat sink to allow adebris-laden portion of the airflow to flow through the bypass channel.5. The system of claim 1, wherein the housing includes a transition sealconfigured to engage the at least one of the fins of the heat sink thatdefines the portion of the inlet airflow passageway to prevent theairflow from flowing between an interface between the at least one ofthe fins and the housing.
 6. The system of claim 5, wherein thetransition seal includes a curved portion and the at least one of thefins includes a complimentary shape to the curved portion.
 7. The systemof claim 1, wherein the at least one of the fins that defines the atleast the portion of the inlet airflow passageway is thicker than one ormore others of the fins in the heat sink.
 8. The system of claim 1,wherein the at least one of the fins that defines the at least theportion of the inlet airflow passageway is in direct thermal contactwith the airflow prior to the airflow flowing through the heat sink. 9.The system of claim 1, wherein the at least one of the fins defines theat least the portion of the inlet airflow passageway by extending alonga side of the inlet airflow passageway.
 10. The system of claim 1,wherein the plural fins include inlet fins and outlet fins, and theinlet fins are disposed within the inlet airflow passageway such thatthe airflow flows between the inlet fins before flowing between theoutlet fins.
 11. The system of claim 10, wherein at least one of theinlet fins or the outlet fins includes fins of varying lengths that arearranged to turn the airflow from the inlet fins to the outlet fins. 12.The system of claim 10, wherein at least one of the inlet fins or theoutlet fins includes curved fins that define vanes arranged to turn theairflow from the inlet fins to the outlet fins.
 13. The system of claim1, wherein the housing includes a restriction element configured toreduce a size of an opening through which the airflow is received intothe inlet airflow passageway, the restriction element configured toincrease a pressure drop of the airflow as the airflow flows into theinlet airflow passageway, through the heat sink, and out of the heatsink.
 14. The system of claim 1, wherein at least one of the fins of theheat sink is divided into a plurality of discrete segments that arespaced apart from each other along a length of the at least one of thefins.
 15. The system of claim 1, wherein at least one of the fins of theheat sink has an undulating body.
 16. The system of claim 1, wherein theheat sink includes a support system having grooves configured to receiveends of the fins, with a first fin of the fins being bent in a firstdirection and a second fin of the fins being bent in an opposite, seconddirection such that the first fin and the second fin are coupledtogether in the heat sink.
 17. A system comprising: a heat sink havingplural fins spaced apart from each other, the fins including inlet finsand outlet fins, with the inlet fins are disposed within an inletairflow passageway that receives airflow to be cooled by the heat sinksuch that the airflow flows between the inlet fins before flowingbetween the outlet fins; wherein at least one of the inlet fins or theoutlet fins are arranged to turn the airflow from the inlet fins to theoutlet fins after the airflow has at least one of flowed through theinlet fins or before the airflow has flowed through the outlet fins. 18.The system of claim 17, wherein the at least one of the inlet fins orthe outlet fins are arranged to turn the airflow toward the outlet finswithout the airflow being turned by a housing disposed outside of oraround the inlet fins or the outlet fins.
 19. The system of claim 17,wherein at least one of the inlet fins or the outlet fins include finsof varying lengths.
 20. The system of claim 19, wherein the inlet finsinclude the fins of varying lengths with the fins having longer lengthslocated along an outside of the heat sink and the fins having decreasinglengths for the fins that are closer to a center of the heat sink. 21.The system of claim 19, wherein the outlet fins include the fins ofvarying lengths with the fins having longer lengths located along acenter of the heat sink and the fins having decreasing lengths for thefins that are closer to the inlet fins.
 22. The system of claim 17,wherein at least one of the inlet fins or the outlet fins includescurved fins that define vanes arranged to turn the airflow from theinlet fins to the outlet fins.
 23. The system of claim 22, wherein theat least one of the inlet fins or the outlet fins that includes thecurved fins also include one or more straight fins disposed between twoor more of the curved fins.
 24. The system of claim 17, wherein at leasttwo of the fins in the heat sink are separated from each other by alarger separation distance than other fins in the heat sink to define abypass channel of the heat sink.
 25. The system of claim 17, wherein thebypass channel in the heat sink is positioned in the heat sink to allowa debris-laden portion of the airflow to flow through the bypasschannel.
 26. The system of claim 17, wherein at least one of the fins isdivided into a plurality of discrete segments that are spaced apart fromeach other along a length of the at least one of the fins.
 27. Thesystem of claim 17, wherein at least one of the fins of the heat sinkhas an undulating body.
 28. The system of claim 17, wherein the heatsink includes a support system having grooves configured to receive endsof the fins, with a first fin of the fins being bent in a firstdirection and a second fin of the fins being bent in an opposite, seconddirection such that the first fin and the second fin are coupledtogether in the heat sink.
 29. A system comprising: a heat sinkconfigured to be disposed in a housing having an inlet airflowpassageway that receives airflow to flow through and be cooled by theheat sink, the heat sink having plural fins spaced apart from each otherand configured to receive the airflow between the fins from the inletairflow passageway of the housing, wherein at least one of the fins ofthe heat sink defines at least a portion of the inlet airflow passagewayin the housing when the heat sink is disposed within the housing. 30.The system of claim 29, wherein an outside fin of the fins in the heatsink is configured to define a portion of the inlet airflow passagewayin the housing along a length of the inlet airflow passageway.
 31. Thesystem of claim 29, wherein at least two of the fins in the heat sinkare separated from each other by a larger separation distance than otherfins in the heat sink to define a bypass channel of the heat sink. 32.The system of claim 29, wherein the at least one of the fins thatdefines the at least the portion of the inlet airflow passageway in thehousing is thicker than one or more others of the fins in the heat sink.33. The system of claim 29, wherein the at least one of the fins thatdefines the at least the portion of the inlet airflow passageway in thehousing is in direct thermal contact with the airflow prior to theairflow flowing through the heat sink when the heat sink is disposedwithin the housing.
 34. The system of claim 29, wherein the at least oneof the fins defines the at least the portion of the inlet airflowpassageway of the housing by extending along a side of the inlet airflowpassageway when the heat sink is disposed within the housing.
 35. Asystem comprising: a housing including an inlet airflow passageway thatis configured to receive airflow from outside of the housing, thehousing configured to receive a heat sink having plural fins spacedapart from each other, wherein the housing is shaped to receive theairflow, direct the airflow through the inlet airflow passageway, andbetween the fins of the heat sink, and wherein the housing is configuredto receive the heat sink into the housing such that at least one of thefins of the heat sink defines at least a portion of the inlet airflowpassageway.
 36. The system of claim 35, wherein the housing isconfigured to receive the heat sink such that an outside fin of the finsin the heat sink is configured to define a portion of the inlet airflowpassageway of the housing along a length of the inlet airflowpassageway.
 37. The system of claim 35, wherein the housing includes atransition seal configured to engage the at least one of the fins of theheat sink that defines the portion of the inlet airflow passageway toprevent the airflow from flowing between an interface between the atleast one of the fins and the housing.
 38. The system of claim 37,wherein the transition seal includes a curved portion and the at leastone of the fins includes a complimentary shape to the curved portion.39. The system of claim 35, wherein the housing is configured to receivethe heat sink such that the at least one of the fins that defines the atleast the portion of the inlet airflow passageway is in direct thermalcontact with the airflow prior to the airflow flowing through the heatsink.
 40. The system of claim 35, wherein the housing includes arestriction element configured to reduce a size of an opening throughwhich the airflow is received into the inlet airflow passageway, therestriction element configured to increase a pressure drop of theairflow as the airflow flows into the inlet airflow passageway, throughthe heat sink, and out of the heat sink.